A Serra High School student was arrested Wednesday in connection with a threatening message, the latest in a month of increasing threats to San Diego schools.
The threat was written on the wall of Serra Mesa High School, according to a letter sent to parents. The student suspected of leaving the message told campus police the threat was not meant to be taken seriously, San Diego Unified School District (SDUSD) officials said.
The threat was deemed unsubstantiated but the student was arrested because the threat was deemed criminal, SDUSD said.
In a letter to parents of students at the high school, Serra High School principal Dr. Erica Renfree said school police have investigated 48 school threats in the weeks following a shooting at Marjory Stoneman Douglas High School in Parkland, Florida that left 17 people, mostly students, dead.
NBC 7 reached out to SDUSD to confirm the number of threats received but have not heard back.
SDUSD is expected to hold a press conference Friday to address the rising number of threats made against schools. San Diego police Chief David Nisliet and District Attorney Summer Stephan were scheduled to attend.
Serra school officials urged parents to speak with their kids about the consequences associated with making these types of threats.
The San Diego County District Attorney's Office brought charges in nine juveniles cases for school threats in San Diego.
In the month following the deadly Parkland high school shooting, law enforcement agencies in San Diego have made several arrests regarding threats.
On March 8, an Olympian High School student was arrested in connection with a threatening message posted on Instagram. Officers went to the student's home and interviewed her and her mother.
The student told police she made the threat as a joke and thought it would be funny.
Three days earlier, a teenager was booked into juvenile hall, accused of making criminal threats on social media aimed at Canyon Crest Academy. The school is in the San Dieguito Union High School District.
A Borrego Springs High School student was suspended on March 1 for threatening to blow up the school. County prosecutors determined no charges would be filed in the case.
On Feb. 27, a Westview High School student was arrested after he was overheard telling classmates to stay home, SDPD investigators said. The unidentified teenager was booked into juvenile hall.
On Feb. 26, a teenager, 17, who was a former student of Torrey Pines High School was arrested and accused of threatening to conduct a shooting at the school. It was the second arrest involving the school. In an unrelated case, a 14-year-old freshman was booked into juvenile hall for making verbal and written threats to harm others, police said.
San Diego police are looking for leads into who tagged various buildings on the campus of Rancho Bernardo High School. The messages discovered by staff on Monday, Feb. 26 referenced the deadly Parkland shooting.
On Feb. 23, an 18-year-old El Centro man was charged with making criminal threats against students and teachers at Imperial High School in Imperial County.
On Feb. 21, San Diego police were made aware of messages on social media threatening a shooting at two Clairemont schools - Madison High School and Creative Performing Media Arts Middle School. The next day, a second message was posted that added San Diego High School and School of Creative and Performing Arts to the list of possible targets. Officials with San Diego Unified School District said the threats were believed to be connected to a middle school student.
On Feb. 20, a message scrolled on the wall of a girls' bathroom prompted an increase in security at High Tech High in Point Loma. That same week, additional security was in place at San Marcos High School for a separate threat and at Scripps Ranch High School following a student's comment perceived to be threatening to public safety.